Retrovirus Emergence among Hunters in Central Africa Both HIV and HTLV have emerged as the result of multiple introductions of nonhuman primate viruses into human populations. Despite the importance of these viruses for human health, the frequency at which these and other potentially novel retroviruses enter into humans and the mechanisms for such cross-species transmission remain unknown. The overall objective of the proposed career development plan is to develop an independent research program to address the frequency, mechanisms, and consequences of retroviral emergence. During the first period of the K01 award (10/99 - 9/03) the PI established a field base for the study of retroviral emergence, obtained training in retroviral research methods, and discovered the first evidence of a link between hunting and retroviral emergence (SFV). During the second period of the K01 award (10/04 - 9/07) the PI proposes to undertake three primary career development activities aimed at advancing research in retroviral emergence: 1) development of an independent laboratory and academic base; 2) development of a competitive R01 grant proposal; and 3) development of novel methods for universal retroviral diagnosis. These activities would take place in the context of a transition to a tenure-track position in molecular epidemiology (beginning 7/03). In this proposal we propose to investigate the persistence, transmissibility, and clinical and immunological manifestations of naturally acquired SFV infection among rural African hunters. The research will include three specific hypotheses: 1) SFV does not persist in a detectable form; 2) SFV is not sexually transmitted; 3) SFV does not result in clinical manifestations. This proposed K01 research component would supplement and leverage a larger award from the US Military HIV Research Program that will support studies of retroviral emergence among a cohort of hunters. Together the career development and research activities proposed in this application will support the development of the PI as a productive independent investigator and advance understanding of how retroviruses enter into human populations.